The cloud of volcanic ash has moved away from British and Irish skies, allowing airspace to reopen.
The high density area of the volcanic ash cloud, which planes cannot fly through, is now off the west coast of Ireland.
Andrew Haines, CAA Chief Executive said ash is likely to continue to disrupt UK air travel for the foreseeable future.
"Scientists are tracking the cloud's movements constantly but its location changes frequently, depending on the strength of eruptions and prevailing winds. When the ash level exceeds that agreed as safe by the industry we have to restrict flights accordingly," warned Haines.
The situation for UK airspace, remains unprecedented, said Haines.
"Volcanic ash is a known hazard to aircraft and the previously accepted procedure adopted all over the world was to avoid ash completely. For the first time an ash cloud is affecting airspace where there is not the room to do this," he said.
"So the CAA had to develop new safety procedures enabling flights to continue whilst flying close to or through the ash cloud. We were able to reopen the skies last month having secured agreement from manufacturers on safe levels of ash tolerance."
www.caa.co.uk